Configuring Annex G - 3Com MSR 50 Series Configuration Manual

244 C 8: F R
HAPTER RAME ELAY

Configuring Annex G

c
C
ONFIGURATION
frame relay routing table of the router. In one route entry, the ingress interface
is tunnel interface and the egress interface is frame relay interface. In the other
route entry, the ingress interface is frame relay interface and the egress
interface is tunnel interface. On the tunnel interface, a virtual circuit whose
DLCI number is out-dlci will be generated. The status of this virtual circuit
determines the status of the above mentioned routes.
The virtual circuit used for frame relay switching must be configured on the
■
tunnel interfaces at both ends of the GRE tunnel, and the DLCI number
(out-dlci) on the tunnel interfaces must be the same.
ANSI T1.617 Annex G (Annex G for short) defines the way to transmit X.25
packets through VCs. In an Annex G implementation, the
acknowledgement/retransmission and flow-control mechanism used in X.25 are
invoked to provide reliable transmission. Annex G can also be used to connect
X.25 networks through FR networks. It is a technology that can help you to
migrate from X.25 network to FR network and thus protects the investment on
X.25 effectively.
Configuration procedure
Follow these steps to configure Annex G:
To do...
Enter system view
Enter interface view
Encapsulate the interface with
FR
Create a VC
Configure the VC interface as
an Annex G interface
CAUTION:
As Annex G is not compliant with Inverse-ARP, you need to configure a static
■
FR mapping for the destination IP address.
An Annex G interface is either a DCE or a DTE. For the two Annex G interfaces
■
of a VC, you need to configure one as the DTE and the other as the DCE.
Configure X.25 parameters for an Annex G interface
Follow these steps to configure X.25 parameters for an Annex G interface:
To do...
Enter system view
Use the command...
system-view
interface interface-type
interface-number
link-protocol fr
fr dlci dlci-number
annexg { dce | dte }
Use the command...
system-view
Remarks
-
-
Required
By default, an interface is
encapsulated with PPP.
Required
This command also leads you
to interface DLCI view.
By default, no VC is created
on an interface.
Required
Remarks
-